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x86: Update _dl_tlsdesc_dynamic to preserve caller-saved registers

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Compiler generates the following instruction sequence for GNU2 dynamic
TLS access:

	leaq	tls_var@TLSDESC(%rip), %rax
	call	*tls_var@TLSCALL(%rax)

or

	leal	tls_var@TLSDESC(%ebx), %eax
	call	*tls_var@TLSCALL(%eax)

CALL instruction is transparent to compiler which assumes all registers,
except for EFLAGS and RAX/EAX, are unchanged after CALL.  When
_dl_tlsdesc_dynamic is called, it calls __tls_get_addr on the slow
path.  __tls_get_addr is a normal function which doesn't preserve any
caller-saved registers.  _dl_tlsdesc_dynamic saved and restored integer
caller-saved registers, but didn't preserve any other caller-saved
registers.  Add _dl_tlsdesc_dynamic IFUNC functions for FNSAVE, FXSAVE,
XSAVE and XSAVEC to save and restore all caller-saved registers.  This
fixes BZ #31372.

Add GLRO(dl_x86_64_runtime_resolve) with GLRO(dl_x86_tlsdesc_dynamic)
to optimize elf_machine_runtime_setup.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
This commit is contained in:
H.J. Lu
2024-02-26 06:37:03 -08:00
parent e6350be7e9
commit 0aac205a81
24 changed files with 914 additions and 207 deletions
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56
sysdeps/x86/cpu-features.c
View File

@ -27,8 +27,13 @@
extern void TUNABLE_CALLBACK (set_hwcaps) (tunable_val_t *)
attribute_hidden;
#if defined SHARED && defined __x86_64__
# include <dl-plt-rewrite.h>
#if defined SHARED
extern void _dl_tlsdesc_dynamic_fxsave (void) attribute_hidden;
extern void _dl_tlsdesc_dynamic_xsave (void) attribute_hidden;
extern void _dl_tlsdesc_dynamic_xsavec (void) attribute_hidden;
# ifdef __x86_64__
# include <dl-plt-rewrite.h>
static void
TUNABLE_CALLBACK (set_plt_rewrite) (tunable_val_t *valp)
@ -47,6 +52,15 @@ TUNABLE_CALLBACK (set_plt_rewrite) (tunable_val_t *valp)
: plt_rewrite_jmp);
}
}
# else
extern void _dl_tlsdesc_dynamic_fnsave (void) attribute_hidden;
# endif
#endif
#ifdef __x86_64__
extern void _dl_runtime_resolve_fxsave (void) attribute_hidden;
extern void _dl_runtime_resolve_xsave (void) attribute_hidden;
extern void _dl_runtime_resolve_xsavec (void) attribute_hidden;
#endif
#ifdef __LP64__
@ -1130,6 +1144,44 @@ no_cpuid:
TUNABLE_CALLBACK (set_x86_shstk));
#endif
if (GLRO(dl_x86_cpu_features).xsave_state_size != 0)
{
if (CPU_FEATURE_USABLE_P (cpu_features, XSAVEC))
{
#ifdef __x86_64__
GLRO(dl_x86_64_runtime_resolve) = _dl_runtime_resolve_xsavec;
#endif
#ifdef SHARED
GLRO(dl_x86_tlsdesc_dynamic) = _dl_tlsdesc_dynamic_xsavec;
#endif
}
else
{
#ifdef __x86_64__
GLRO(dl_x86_64_runtime_resolve) = _dl_runtime_resolve_xsave;
#endif
#ifdef SHARED
GLRO(dl_x86_tlsdesc_dynamic) = _dl_tlsdesc_dynamic_xsave;
#endif
}
}
else
{
#ifdef __x86_64__
GLRO(dl_x86_64_runtime_resolve) = _dl_runtime_resolve_fxsave;
# ifdef SHARED
GLRO(dl_x86_tlsdesc_dynamic) = _dl_tlsdesc_dynamic_fxsave;
# endif
#else
# ifdef SHARED
if (CPU_FEATURE_USABLE_P (cpu_features, FXSR))
GLRO(dl_x86_tlsdesc_dynamic) = _dl_tlsdesc_dynamic_fxsave;
else
GLRO(dl_x86_tlsdesc_dynamic) = _dl_tlsdesc_dynamic_fnsave;
# endif
#endif
}
#ifdef SHARED
# ifdef __x86_64__
TUNABLE_GET (plt_rewrite, tunable_val_t *,